Systems and methods for detecting radar

ABSTRACT

A system includes a first-in first-out (FIFO) module, a polling module, a data extraction module, and a control module. The FIFO module receives records having dynamic frequency selection (DFS) information generated based on pulses received and generates a control signal for every N of the records received, where N is an integer greater than or equal to 1. The polling module selectively polls the FIFO module and reads M of the records received by the FIFO module, where M is an integer greater than or equal to 1 and less than N. The data extraction module extracts the DFS information from the N records when the control signal is received and selectively extracts the DFS information from the M records. The control module determines whether the pulses are a type of radar based on the DFS information extracted from at least N of the (N+M) of the records.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/817,325 filed on Jun. 29, 2006. The disclosure of the aboveapplication is incorporated herein by reference in its entirety.

FIELD

The present disclosure relates to wireless networks, and moreparticularly to systems and methods for detecting radar signals inwireless network devices.

BACKGROUND

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description which may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

The I.E.E.E. has defined various standards for configuring wirelessnetworks and devices. For example, 802.11, 802.11(a), 802.11(b),802.11(g), 802.11(h), 802.11(n), 802.16, and 802.20. According to thesestandards, wireless network devices may be operated in either aninfrastructure mode or an ad-hoc mode. In the infrastructure mode, thewireless network devices or client stations communicate with each otherthrough an access point. In the ad-hoc mode, the wireless networkdevices communicate directly with each other and do not employ an accesspoint.

Referring now to FIG. 1, a first wireless network 10 is illustrated inan infrastructure mode. The first wireless network 10 includes one ormore client stations 12 and one or more access points (AP) 14. Theclient station 12 and the AP 14 transmit and receive wireless signals16. The AP 14 is a node in a network 18. The network 18 may be a localarea network (LAN), a wide area network (WAN), or another networkconfiguration. The network 18 may include other nodes such as a server20 and may be connected to a distributed communications system 22 suchas the Internet.

Referring now to FIG. 2, a second wireless network 24 operates in anad-hoc mode. The second wireless network 24 includes multiple clientstations 26-1, 26-2, and 26-3 that transmit and receive wireless signals28. The client stations 26-1, 26-2, and 26-3 collectively form a LAN andcommunicate directly with each other. The client stations 26-1, 26-2,and 26-3 are not necessarily connected to another network.

To minimize radio frequency (RF) interference, some wireless networksmay operate in a 5 GHz band. However, regulatory requirements governingthe use of the 5 GHz band vary from country to country. For example,some countries utilize the 5 GHz band for military radar communications.Therefore, wireless networks operating in the 5 GHz band generallyemploy dynamic frequency selection (DFS) to avoid interference withradar communications. Specifically, wireless network devices generallyemploy DFS to switch to a different channel of the 5 GHz band to avoidinterfering with radar communications.

In infrastructure mode, the AP 14 transmits beacons to inform the clientstations 12 that the AP uses DFS. When the client stations 12 detectradar on a channel, the client stations 12 notify the AP 14. Based onthis information, the AP 14 uses DFS to select the best channel fornetwork communications that will not interfere with radar.

In ad-hoc mode, one client station may be designated as a DFS owner. TheDFS owner is responsible for collecting information from other clientstations. If any client station in the ad-hoc network detects radar, theDFS owner uses DFS to select the best channel for network communicationsthat does not interfere with radar. For example, if station 26-1 is theDFS owner, it is responsible for collecting information from stations26-2 and 26-3. If any of the stations 26-1, 26-2, and 26-3 detectsradar, station 26-1 uses DFS to select the best channel and notifystations 26-2 and 26-3 to switch to that channel.

Referring now to FIGS. 3A-3C, radar signals generally comprise bursts ofpulses that have predetermined pulse widths and pulse repetition rates.FIG. 3A shows a burst of radar. Radar signals can be tone or chirp type.Frequency of tone type radar pulses is generally fixed, whereasfrequency of chirp type radar pulses may vary linearly. Based oncharacteristics such as pulse width (PW), pulse repetition rate (PRI),etc., radar signals may be classified into different types. For example,a table in FIG. 3B shows types of radar signals and respective standardsspecified by the federal communications commission (FCC). Similarly, atable in FIG. 3C shows types of radar signals and respective standardsspecified by the European telecommunications standards institute (ETSI).

SUMMARY

A system comprises a first-in first-out (FIFO) module, a polling module,a data extraction module, and a control module. The FIFO module receivesrecords having dynamic frequency selection (DFS) information generatedbased on pulses received and generates a control signal for every N ofthe records received, where N is an integer greater than or equal to 1.The polling module selectively polls the FIFO module and reads M of therecords received by the FIFO module, where M is an integer greater thanor equal to 1 and less than N. The data extraction module extracts theDFS information from the N of the records when the control signal isreceived and selectively extracts the DFS information from the M of therecords. The control module determines whether the pulses are a type ofradar based on the DFS information extracted from at least N of the(N+M) of the records.

In another feature, the DFS information comprises pulse widths and pulserepetition rates of the pulses, signal strength of radio frequency (RF)signals in the pulses, and whether the pulses are one of a tone type anda chirp type radar pulses.

In another feature, the polling module polls the FIFO module when theDFS information extracted from a predetermined number of records out ofthe N of the records indicates that the pulses are not radar pulses.

In another feature, the system further comprises a buffer module thatstores the DFS information extracted by the data extraction module.

In another feature, The pulses are received from at least one burst ofradar.

In another feature, the control module determines that the pulses are atype of tone radar when the DFS information extracted from each of theat least N of the (N+M) of the records includes information that acorresponding one of the pulses is a tone radar pulse, an average ofpulse widths in the DFS information extracted from each of the at leastN of the (N+M) of the records approximately matches a pulse width of apredetermined type of tone radar, a difference between a maximum and aminimum of the pulse widths is less than a predetermined threshold, andpulse repetition intervals in the DFS information extracted from apredetermined number of the at least N of the (N+M) of the recordsapproximately match a pulse repetition interval of the predeterminedtype of tone radar.

In another feature, the control module determines that the pulses are atype of chirp radar when the DFS information extracted from each of theat least N of the (N+M) of the records includes information that acorresponding one of the pulses is a chirp radar pulse, pulse widths inthe DFS information extracted from the at least N of the (N+M) of therecords approximately match pulse widths of a predetermined type ofchirp radar, and pulse repetition intervals in the DFS informationextracted from a predetermined number of the at least N of the (N+M) ofthe records approximately match pulse repetition intervals of thepredetermined type of chirp radar.

In another feature, the control module determines whether the pulses area type of one of a tone radar and a chirp radar based on pulse widths inthe DFS information extracted from at least N of the records when thepulses are received from at least one burst of radar and when the pulsesare separated by at least one data packet.

In another feature, the control module determines that the pulses are atype of tone radar when the pulse widths match a pulse width of apredetermined type of tone radar and wherein the control moduledetermines that the pulses are a type of chirp radar when the pulsewidths match pulse widths of a predetermined type of chirp radar.

In another feature, the pulses comprise radio frequency (RF) signals andthe DFS information includes a number of zero-crossings of the RFsignals per bin for a plurality of bins, where the bin is a time periodgreater than or equal to a smallest of pulse widths of predeterminedtypes of radar pulses.

In another feature, the control module determines that the pulses aretone type radar pulses when a difference between maximum and minimumvalues of the number of zero-crossings is less than a predeterminedthreshold.

In another feature, the control module determines that the pulses arechirp type radar pulses when differences between the number ofzero-crossings in adjacent bins are greater than a first predeterminedthreshold and a rate of change of the number of zero-crossings insuccessive bins is less than a second predetermined threshold.

In another feature, a medium access controller (MAC) comprises thesystem and further comprises a physical layer module (PHY) thatcommunicates the records to the MAC.

In another feature, a wireless network device comprises the MAC andfurther comprises at least one antenna that receives the pulses and thatcommunicates the pulses to the PHY.

In another feature, a radar detection device comprises the system.

In still other features, a method comprises receiving records havingdynamic frequency selection (DFS) information generated based on pulsesreceived in a first-in first-out (FIFO) module and generating a controlsignal for every N of the records received, where N is an integergreater than or equal to 1. The method further comprises selectivelypolling the FIFO module and reading M of the records received by theFIFO module, where M is an integer greater than or equal to 1 and lessthan N. The method further comprises extracting the DFS information fromthe N of the records when the control signal is received, selectivelyextracting the DFS information from the M of the records, anddetermining whether the pulses are a type of radar based on the DFSinformation extracted from at least N of the (N+M) of the records.

In another feature, the method further comprises receiving the recordshaving the DFS information that includes pulse widths and pulserepetition rates of the pulses, signal strength of radio frequency (RF)signals in the pulses, and whether the pulses are one of a tone type anda chirp type radar pulses.

In another feature, the method further comprises polling the FIFO modulewhen the DFS information extracted from a predetermined number ofrecords out of the N of the records indicates that the pulses are notradar pulses.

In another feature, the method further comprises storing the DFSinformation extracted by the data extraction module.

In another feature, the method further comprises receiving the pulsesfrom at least one burst of radar.

In another feature, the method further comprises determining that thepulses are a type of tone radar when the DFS information extracted fromeach of the at least N of the (N+M) of the records includes informationthat a corresponding one of the pulses is a tone radar pulse, an averageof pulse widths in the DFS information extracted from each of the atleast N of the (N+M) of the records approximately matches a pulse widthof a predetermined type of tone radar, a difference between a maximumand a minimum of the pulse widths is less than a predeterminedthreshold, and pulse repetition intervals in the DFS informationextracted from a predetermined number of the at least N of the (N+M) ofthe records approximately match a pulse repetition interval of thepredetermined type of tone radar.

In another feature, the method further comprises determining that thepulses are a type of chirp radar when the DFS information extracted fromeach of the at least N of the (N+M) of the records includes informationthat a corresponding one of the pulses is a chirp radar pulse, pulsewidths in the DFS information extracted from the at least N of the (N+M)of the records approximately match pulse widths of a predetermined typeof chirp radar, and pulse repetition intervals in the DFS informationextracted from a predetermined number of the at least N of the (N+M) ofthe records approximately match pulse repetition intervals of thepredetermined type of chirp radar.

In another feature, the method further comprises determining whether thepulses are a type of one of a tone radar and a chirp radar based onpulse widths in the DFS information extracted from at least N of therecords when the pulses are received from at least one burst of radarand when the pulses are separated by at least one data packet.

In another feature, the method further comprises determining that thepulses are a type of tone radar when the pulse widths match a pulsewidth of a predetermined type of tone radar and determining that thepulses are a type of chirp radar when the pulse widths match pulsewidths of a predetermined type of chirp radar.

In another feature, the method further comprises receiving the recordswhen the pulses include radio frequency (RF) signals and wherein the DFSinformation includes a number of zero-crossings of the RF signals perbin for a plurality of bins, where the bin is a time period greater thanor equal to a smallest of pulse widths of predetermined types of radarpulses.

In another feature, the method further comprises determining that thepulses are tone type radar pulses when a difference between maximum andminimum values of the number of zero-crossings is less than apredetermined threshold.

In another feature, the method further comprises determining that thepulses are chirp type radar pulses when differences between the numberof zero-crossings in adjacent bins are greater than a firstpredetermined threshold, and a rate of change of the number ofzero-crossings in successive bins is less than a second predeterminedthreshold.

In another feature, the method further comprises communicating between aphysical layer module (PHY) and a medium access controller (MAC) andcommunicating the records to the MAC.

In another feature, the method further comprises receiving the pulsesvia at least one antenna in a wireless network device and communicatingthe pulses to the PHY.

In another feature, the method further comprises determining whether thepulses include radar when the pulses are received by a radar detectiondevice.

In still other features, a system comprises first-in first-out (FIFO)means for receiving records having dynamic frequency selection (DFS)information generated based on pulses received and generating a controlsignal for every N of the records received, where N is an integergreater than or equal to 1. The system further comprises polling meansfor selectively polling the FIFO means and reading M of the recordsreceived by the FIFO means, where M is an integer greater than or equalto 1 and less than N. The system further comprises data extraction meansfor extracting the DFS information from the N of the records when thecontrol signal is received and selectively extracting the DFSinformation from the M of the records, and control means for determiningwhether the pulses are a type of radar based on the DFS informationextracted from at least N of the (N+M) of the records.

In another feature, the DFS information comprises pulse widths and pulserepetition rates of the pulses, signal strength of radio frequency (RF)signals in the pulses, and whether the pulses are one of a tone type anda chirp type radar pulses.

In another feature, the polling means polls the FIFO means when the DFSinformation extracted from a predetermined number of records out of theN of the records indicates that the pulses are not radar pulses.

In another feature, the system further comprises buffer means forstoring the DFS information extracted by the data extraction means.

In another feature, the pulses are received from at least one burst ofradar.

In another feature, the control means determines that the pulses are atype of tone radar when the DFS information extracted from each of theat least N of the (N+M) of the records includes information that acorresponding one of the pulses is a tone radar pulse, an average ofpulse widths in the DFS information extracted from each of the at leastN of the (N+M) of the records approximately matches a pulse width of apredetermined type of tone radar, a difference between a maximum and aminimum of the pulse widths is less than a predetermined threshold, andpulse repetition intervals in the DFS information extracted from apredetermined number of the at least N of the (N+M) of the recordsapproximately match a pulse repetition interval of the predeterminedtype of tone radar.

In another feature, the control means determines that the pulses are atype of chirp radar when the DFS information extracted from each of theat least N of the (N+M) of the records includes information that acorresponding one of the pulses is a chirp radar pulse, pulse widths inthe DFS information extracted from the at least N of the (N+M) of therecords approximately match pulse widths of a predetermined type ofchirp radar, and pulse repetition intervals in the DFS informationextracted from a predetermined number of the at least N of the (N+M) ofthe records approximately match pulse repetition intervals of thepredetermined type of chirp radar.

In another feature, the control means determines whether the pulses area type of one of a tone radar and a chirp radar based on pulse widths inthe DFS information extracted from at least N of the records when thepulses are received from at least one burst of radar and when the pulsesare separated by at least one data packet.

In another feature, the control means determines that the pulses are atype of tone radar when the pulse widths match a pulse width of apredetermined type of tone radar and wherein the control meansdetermines that the pulses are a type of chirp radar when the pulsewidths match pulse widths of a predetermined type of chirp radar.

In another feature, the pulses comprise radio frequency (RF) signals andthe DFS information includes a number of zero-crossings of the RFsignals per bin for a plurality of bins, where the bin is a time periodgreater than or equal to a smallest of pulse widths of predeterminedtypes of radar pulses.

In another feature, the control means determines that the pulses aretone type radar pulses when a difference between maximum and minimumvalues of the number of zero-crossings is less than a predeterminedthreshold.

In another feature, the control means determines that the pulses arechirp type radar pulses when differences between the number ofzero-crossings in adjacent bins are greater than a first predeterminedthreshold, and a rate of change of the number of zero-crossings insuccessive bins is less than a second predetermined threshold.

In another feature, a medium access controller (MAC) comprises thesystem and further comprises physical layer means (PHY) forcommunicating the records to the MAC.

In another feature, a wireless network device comprises the MAC andfurther comprises at least one antenna means for receiving the pulsesand communicating the pulses to the PHY means.

In another feature, a radar detection device comprises the system.

In still other features, a computer program executed by a processorcomprises receiving records having dynamic frequency selection (DFS)information generated based on pulses received in a first-in first-out(FIFO) module and generating a control signal for every N of the recordsreceived, where N is an integer greater than or equal to 1. The computerprogram further comprises selectively polling the FIFO module andreading M of the records received by the FIFO module, where M is aninteger greater than or equal to 1 and less than N. The computer programfurther comprises extracting the DFS information from the N of therecords when the control signal is received, selectively extracting theDFS information from the M of the records, and determining whether thepulses are a type of radar based on the DFS information extracted fromat least N of the (N+M) of the records.

In another feature, the computer program further comprises receiving therecords having the DFS information that includes pulse widths and pulserepetition rates of the pulses, signal strength of radio frequency (RF)signals in the pulses, and whether the pulses are one of a tone type anda chirp type radar pulses.

In another feature, the computer program further comprises polling theFIFO module when the DFS information extracted from a predeterminednumber of records out of the N of the records indicates that the pulsesare not radar pulses.

In another feature, the computer program further comprises storing theDFS information extracted by the data extraction module.

In another feature, the computer program further comprises receiving thepulses from at least one burst of radar.

In another feature, the computer program further comprises determiningthat the pulses are a type of tone radar when the DFS informationextracted from each of the at least N of the (N+M) of the recordsincludes information that a corresponding one of the pulses is a toneradar pulse, an average of pulse widths in the DFS information extractedfrom each of the at least N of the (N+M) of the records approximatelymatches a pulse width of a predetermined type of tone radar, adifference between a maximum and a minimum of the pulse widths is lessthan a predetermined threshold, and pulse repetition intervals in theDFS information extracted from a predetermined number of the at least Nof the (N+M) of the records approximately match a pulse repetitioninterval of the predetermined type of tone radar.

In another feature, the computer program further comprises determiningthat the pulses are a type of chirp radar when the DFS informationextracted from each of the at least N of the (N+M) of the recordsincludes information that a corresponding one of the pulses is a chirpradar pulse, pulse widths in the DFS information extracted from the atleast N of the (N+M) of the records approximately match pulse widths ofa predetermined type of chirp radar, and pulse repetition intervals inthe DFS information extracted from a predetermined number of the atleast N of the (N+M) of the records approximately match pulse repetitionintervals of the predetermined type of chirp radar.

In another feature, the computer program further comprises determiningwhether the pulses are a type of one of a tone radar and a chirp radarbased on pulse widths in the DFS information extracted from at least Nof the records when the pulses are received from at least one burst ofradar and when the pulses are separated by at least one data packet.

In another feature, the computer program further comprises determiningthat the pulses are a type of tone radar when the pulse widths match apulse width of a predetermined type of tone radar and determining thatthe pulses are a type of chirp radar when the pulse widths match pulsewidths of a predetermined type of chirp radar.

In another feature, the computer program further comprises receiving therecords when the pulses include radio frequency (RF) signals and whereinthe DFS information includes a number of zero-crossings of the RFsignals per bin for a plurality of bins, where the bin is a time periodgreater than or equal to a smallest of pulse widths of predeterminedtypes of radar pulses.

In another feature, the computer program further comprises determiningthat the pulses are tone type radar pulses when a difference betweenmaximum and minimum values of the number of zero-crossings is less thana predetermined threshold.

In another feature, the computer program further comprises determiningthat the pulses are chirp type radar pulses when differences between thenumber of zero-crossings in adjacent bins are greater than a firstpredetermined threshold, and a rate of change of the number ofzero-crossings in successive bins is less than a second predeterminedthreshold.

In another feature, the computer program further comprises communicatingbetween a physical layer module (PHY) and a medium access controller(MAC) and communicating the records to the MAC.

In another feature, the computer program further comprises receiving thepulses via at least one antenna in a wireless network device andcommunicating the pulses to the PHY.

In another feature, the computer program further comprises determiningwhether the pulses include radar when the pulses are received by a radardetection device.

In still other features, the systems and methods described above areimplemented by a computer program executed by one or more processors.The computer program can reside on a computer readable medium such asbut not limited to memory, non-volatile data storage and/or othersuitable tangible storage mediums.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the disclosure, are intended forpurposes of illustration only and are not intended to limit the scope ofthe disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is functional block diagram of a wireless network operating in aninfrastructure mode according to the prior art;

FIG. 2 is a function block diagram of a wireless network operating in anad-hoc mode according to the prior art;

FIG. 3A shows a burst of pulses in a radar signal;

FIG. 3B is a table listing parameters of different types of radarsignals in the United States;

FIG. 3C is a table listing parameters of different types of radarsignals in Europe;

FIG. 4A is a functional block diagram of an exemplary system fordetecting radar in a wireless network device according to the presentdisclosure;

FIG. 4B depicts a sliding-window scheme used by the system of FIG. 4A todetect radar according to the present disclosure;

FIG. 4C shows radar pulses in a burst of radar;

FIG. 4D shows radar pulses in two bursts of radar;

FIG. 4E shows radar pulses in multiple bursts of radar separated by datapackets;

FIG. 5A shows zero-crossings of a radio frequency signal in a bin;

FIG. 5B is a graph of number of zero-crossings per bin as a function ofnumber of bins for a tone type radar;

FIG. 5C is a graph of number of zero-crossings per bin relative as afunction of number of bins for a chirp type radar;

FIG. 6A shows a first portion of a flowchart of an exemplary method fordetecting radar in a wireless network device according to the presentdisclosure;

FIG. 6B shows a second portion of the flowchart of the exemplary methodfor detecting radar in a wireless network device according to thepresent disclosure;

FIG. 7A is a functional block diagram of a high definition television;

FIG. 7B is a functional block diagram of a vehicle control system;

FIG. 7C is a functional block diagram of a cellular phone;

FIG. 7D is a functional block diagram of a set top box; and

FIG. 7E is a functional block diagram of a mobile device.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is in no wayintended to limit the disclosure, its application, or uses. For purposesof clarity, the same reference numbers will be used in the drawings toidentify similar elements. As used herein, the term module, circuitand/or device refers to an Application Specific Integrated Circuit(ASIC), an electronic circuit, a processor (shared, dedicated, or group)and memory that execute one or more software or firmware programs, acombinational logic circuit, and/or other suitable components thatprovide the described functionality. As used herein, the phrase at leastone of A, B, and C should be construed to mean a logical (A or B or C),using a non-exclusive logical or. It should be understood that stepswithin a method may be executed in different order without altering theprinciples of the present disclosure.

Systems and methods for detecting radar in wireless networks aredisclosed in U.S. patent application Ser. No. 11/493,473 filed on Jul.26, 2006, which is incorporated herein by reference in its entirety. Thesystems and methods may be implemented in at least one of a basebandprocessor (BBP) and a medium access controller (MAC) of a wirelessnetwork device. The systems and methods detect radar by analyzingisolated pulses. Consequently, the systems and methods may mis-detectradar when the pulses are generated by noise or interference. Radar maybe correctly detected by analyzing a series of pulses in a burst orbursts of radar.

Referring now to FIGS. 4A-4E, a system 100 for detecting radar comprisesa MAC FIFO module 102 and a radar detection module 104. The radardetection module 104 comprises a data extraction module 106, a buffermodule 108, a control module 110, and a polling module 112. When awireless network device (not shown) receives pulses that are radarpulses or may be radar pulses, the wireless network device may performdynamic frequency selection (DFS) and may communicate on a channel otherthan the current channel.

When the pulses received by the wireless network device are radar pulsesor may be radar pulses, a BBP in the wireless network device maygenerate a 64-byte DFS record for each pulse. The DFS record may include8 bytes of DFS information, such as radar type (tone or chirp), pulsewidth (PW), pulse repetition rate (PRI), etc., and 56 bytes of frequencyinformation.

A MAC FIFO module 102 in the wireless network device receives the DFSrecords from the BBP. The memory size of the MAC FIFO module 102,however, is generally limited. Thus, the number of DFS records that maybe queued in the MAC FIFO module 102 may be limited and may bedetermined by a queue size. The queue size may be programmable and maybe set to 10, for example.

When the MAC FIFO module 102 receives a predetermined number of DFSrecords called a window size (W), which is less than the queue size, theMAC FIFO module 102 generates an interrupt or a control signal. Uponreceiving the interrupt, the radar detection module 104 analyzes the DFSrecords and determines the type of radar received by the BBP. W isprogrammable and may typically be set to half the queue size. Thus, Wmay be five if the queue size is 10, and the MAC FIFO module 102 maygenerate the interrupt after receiving five DFS records. A maximum valueof W is less than or equal to a DFS interrupt threshold.

Upon receiving the control signal, the data extraction module 106extracts the DFS information from the five DFS records and outputs theDFS information to the buffer module 108. The memory size of the buffermodule 108 is generally greater than the memory size of the MAC FIFOmodule 102. The buffer module 108 stores the DFS information inlocations starting at a location determined by a write pointer as shownin FIG. 4B. Additionally, when the BBP is unable to validate frequencyinformation, the buffer module 108 may store the frequency informationof the DFS records for subsequent validation.

A read pointer in the buffer module 108 determines a location from wherethe control module 110 begins reading DFS information as shown in FIG.4B. The control module 110 reads DFS information stored in (readpointer+W) locations in the buffer module 108 and processes the DFSinformation to determine the type of radar pulses received by thewireless network device. The control module 110 increments the readpointer after processing the DFS information. Effectively, the windowcomprising W locations moves or slides to next W locations in the buffermodule 108 during each processing cycle. Thus, the window may be calleda moving or a sliding window of size W.

The system 100 can correctly detect the type of radar if the buffermodule 108 receives at least five records indicating that the pulses areradar pulses. Occasionally, however, due to noise or interference (e.g.,spikes generated by microwave devices), some of the DFS records may becorrupted. For example, when W=5, DFS record numbers 2 and 3 may becorrupted. In that case, the DFS information in the corrupted recordsmay indicate that the received pulses are not radar pulses.

The control module 110 analyzes the DFS information in the W records. Ifthe control module 110 determines that a majority of the DFS recordsindicate that the received pulses are radar pulses, the polling module112 performs interrupt driven polling. The polling module 112 retrievesadditional records from the MAC FIFO module 102 before the MAC FIFOmodule 102 generates the next interrupt.

Specifically, the control module 110 checks the DFS information in (readpointer+W) locations in the buffer module 108. If the DFS information ina majority of the W locations (e.g., three out of five) indicates thatthe received pulses are of a known type of radar, the control module 110outputs a polling signal to the polling module 112. The polling module112 initiates a timer or a counter (not shown) that is set to count apredetermined time equal to T*X μS, where X=16 μS if the wirelessnetwork device is FCC-compliant and X=32 μS if the wireless networkdevice is ETSI-compliant. T is selected such that the predetermined timeis at least equal to the duration of a longest radar burst.

While the timer is counting, the polling module 112 polls the MAC FIFOmodule 102 and checks if any additional DFS records are receivedsubsequent to the last interrupt. The polling module 112 retrieves anyadditional DFS records received by the MAC FIFO module 102 and outputsthe additional DFS records to the data extraction module 106. The dataextraction module 106 extracts the DFS information (and optionally, thefrequency information) from the additional DFS records. The buffermodule 108 stores the DFS information from the additional DFS records inlocations starting at the current location of the write pointer.

When the timer expires, the control module 110 checks the location ofthe write pointer to determine if the buffer module 108 received anyadditional DFS information. If the buffer module 108 received additionalDFS information and has valid DFS information in a total of at least Wlocations, the control module 110 analyses the DFS information in the Wlocations as follows.

The control module 110 compares the PW and PRI data in the DFSinformation in W locations to the PW and PRI data of known types ofradar, which is tabulated in FIGS. 3B-3C. The control module 110 maystore the PW and PRI data of the known types of radar in the form of alook-up table in memory. Typically, the look-up table may include radarpatterns having predetermined PW-PRI relationships, which are tabulatedin FIGS. 3B-3C. Comparing the PW and PRI data in W locations with radarpatterns in the look-up table may be faster than individually comparingthe PW and PRI data with each PW and PRI of each type of radar.

Alternately, the look-up table may include acceptable PRI valuescorresponding different PW values of known types of radar. In that case,the control module 110 may only determine whether the PW data in the DFSinformation matches PW of a known type of radar. Subsequently, thecontrol module 110 may find corresponding acceptable PRI (and the typeof radar) by comparing the PW data to the PW values in the look-up tableinstead of actually determining PRI and then comparing the PRI to thePRI data of all known types of radar.

The control module 110 uses different comparison criteria to determinethe type of radar since DFS records may be generated in different ways.For example, the five DFS records may be generated by five consecutiveradar pulses in the same burst having identical PW and PRI as shown inFIG. 4C or by a total five pulses from two consecutive bursts havingidentical PW but unequal PRI as shown in FIG. 4D. In either case, thecontrol module 110 determines which type of tone or chirp radar may bepresent in the pulses received by the BBP as follows.

If the DFS information in all five records indicates that the radarpulses are tone type, then the control module 110 compares the PW andPRI data in each record with the PW and PRI data of known types ofradar. Specifically, the control module 110 determines whether thedifference between a maximum pulse width and a minimum pulse width ofthe five pulse widths in the five records is less than or equal to athreshold pulse width, which may be equal to 2 μS.

Additionally, the control module 110 determines whether the average ofthe maximum and minimum pulse widths matches a valid pulse width (i.e.,a pulse width of a known type of radar). The value of the valid pulsewidth may differ depending on whether the radar pulses are FCC-compliantor ETSI-compliant. Finally, since the radar pulses may be from twoconsecutive bursts, the control module 110 determines whether the PRIdata in a majority of the five records (e.g., three of five records)matches the PRI of a known type of tone radar having the valid PW.

If, however, the DFS information in all five records indicates that theradar pulses are chirp type, then the control module 110 compares the PWand PRI data in each record with the PW and PRI data of known types ofradar. Since PW and PRI are variable in chirp radar, the control module110 determines whether the pulse widths in the five recordsapproximately match one of the known chirp radar patterns shown in FIG.3B or 3C. Additionally, the control module 110 determines whether thePRI data in a majority of the five records (e.g., three of five records)approximately matches the PRI of a known type of chirp radar.

Occasionally, the BBP may simultaneously receive radar and packets ofwireless data (or interference) as shown in FIG. 4E. In that case, theBBP may receive radar pulses from different bursts as shown.Additionally, pulse widths of received radar pulses may be identical incase of tone radar or variable in case of chirp radar. Thus, the PW (orpulse widths in case of a chirp radar) in the five records may match PW(or pulse widths) of a known type of tone (or chirp) radar. In eithercase, however, the PRI of the received pulses may vary due to thepresence of packets of wireless data (or interference) between the radarpulses. Thus, the control module 110 cannot accurately determine thetype of radar by comparing PRI in any of the five records to the PRI ofknown types tone and/or chirp radar.

Since PRI cannot be used to accurately determine the type of radar, thecontrol module 110 increases the window size and compares PW data in theincreased number of records to confirm the type of radar. For example,the window size may be increased from five to eight and read DFSinformation stored in locations (read pointer−3) to (read pointer+4) inthe buffer module 108. In that case, the control module 110 may comparePW data from all eight records to the PW (or pulse widths in case ofchirp radar) of known types of tone (or chirp) radar. Alternatively, thewindow size may be increased from five to ten, and PW from a majority ofrecords (e.g., seven or eight of the ten records) may be compared to thePW (or pulse widths in case of chirp radar) of known types of radar.

Occasionally, due to noise or interference, the BBP may be unable tocorrectly validate frequency information of the radar pulses. In thatcase, the control module 110 processes the frequency information in the56 bytes of the W records to determine whether the pulses that generatedthe W records are of tone or chirp type.

Referring now to FIGS. 5A-5C, a radio frequency (RF) signal in a radarpulse transitions multiple times between high and low states as shown inFIG. 5A. During each transition, the RF signal crosses a point in time,called a zero-crossing point, where the amplitude of the RF signal isapproximately zero as shown. A bin or bin size is a predetermined timeperiod within which the RF signal crosses points of zero-amplitude apredetermined number of times. That is, the RF signal has apredetermined number of zero-crossings within a predetermined bin size.The number of zero-crossings within a bin and the bin size for aparticular type of radar are determined based on the FCC or ETSIstandards. Typically, the bin size is at least equal to a minimum pulsewidth of all radar signals. For example, the bin size may be at least 2μS.

The frequency information in each of the five records includes number ofzero-crossings. The number of zero-crossings for tone radar isapproximately the same in different bins as shown in FIG. 5B. Thecontrol module 110 determines whether a difference between maximum andminimum number of zero-crossings in all bins is less than or equal to apredetermined threshold, called a tone zero-crossing threshold(Threshold_(tone)). If true, the control module 110 determines that theradar pulses are tone type.

On the other hand, the frequency of the RF signal varies linearly inchirp radar. Consequently, the number of zero-crossings in each bin mayvary from bin to bin as shown in FIG. 5C. Zero-crossings less than apredetermined threshold are disregarded in determining whether the radaris chirp radar. If the difference d_(i) between the number ofzero-crossings in adjacent bins for all i bins is greater thanThreshold_(tone), the control module 110 determines that the radar isnot a tone radar. That is, if d1 denotes the number of zero-crossings inbin1, d2 denotes the number of zero-crossings in bin2, etc., then theradar is not a tone radar if (d_(i)−d_(i+1))>Threshold_(tone) for all i.

For a linear chirp radar, the rate of change of zero-crossings (denotedby the slope of the plots in FIG. 5C) between adjacent bins isapproximately the same. The control module 110 determines whether theabsolute value of the differences in number of zero-crossings betweenadjacent bins (i.e., |(d_(i)−d_(i+1))|) for all i bins is less than apredetermined threshold called a chirp zero-crossing threshold(Threshold_(chirp)). If true, the control module 110 determines that theradar is chirp type.

Referring now to FIGS. 6A-6B, a method 200 for detecting radar in awireless network device begins at step 202. A media access controller(MAC) determines in step 204 if the wireless network device isperforming dynamic frequency selection (DFS). If true, a basebandprocessor (BBP) outputs records comprising DFS information to a MAC FIFOmodule 102 in step 206.

The MAC FIFO module 102 checks in step 208 if the number of recordsqueued is greater than or equal to a window size (e.g., five). If true,the MAC FIFO module 102 generates an interrupt or a control signal instep 210. Upon receiving the interrupt, a data extraction module 106receives the five records from the MAC FIFO module 102 and extracts DFSinformation from each of the five records in step 212. The DFSinformation is stored in a buffer module 108 in step 214.

A control module 110 checks in step 216 if the DFS information in allfive records indicates that the received pulses are radar pulses. Iffalse, the control module 110 determines in step 218 if the DFSinformation in a majority of the five records (e.g., three of five)indicates that the received pulses are radar pulses. If false, steps 204through 218 are repeated.

If the result of step 218 is true, a polling module 112 starts a timerin step 220. The timer counts a predetermined period of time in step222. The MAC FIFO module 102 determines in step 224 if five more recordsare received in the queue to generate next interrupt. If true, thecontrol module 110 resets the timer in step 226, and steps starting fromstep 212 are repeated.

If the result of step 224 is false, the control module 110 checks instep 228 if the timer finished counting time. If false, steps startingat step 222 are repeated. If the timer finished counting time and theMAC FIFO module 102 did not generate another interrupt, the pollingmodule 112 checks in step 230 if the MAC FIFO module 102 received anymore records. If false, steps starting at 220 are repeated. If true, thepolling module 112 receives additional records from the MAC FIFO module102 in step 232, and steps starting step 212 are repeated.

If the result of step 216 is true, the control module 110 determines instep 234 if the DFS information in all five records indicates that thereceived pulses are of tone type radar. If false, the control module 110determines in step 236 if the DFS information in all five recordsindicates that the received pulses are of chirp type radar.

If the results of steps 234 and 236 are true, the control module 110determines in step 238 if pulse width information in the five recordsmatches with the pulse width information of a known tone or chirp radar.If false, the control module 110 determines in step 240 that the pulsesreceived are not radar pulses, and steps starting at step 204 arerepeated. If true, however, the control module 110 determines in step242 if PRI information in a majority of the five records matches the PRIinformation of a known tone or chirp radar. If true, the control module110 generates a control signal in step 244 identifying the type ofdetected radar.

If the results of steps 236 and 244 are false, then in step 246, thecontrol module 110 increases the window size (e.g., from five to eight),reads additional records stored in the buffer module 108, and stepsstarting at step 234 are repeated.

Referring now to FIGS. 7A-7E, various exemplary implementationsincorporating the teachings of the present disclosure are shown.Referring now to FIG. 7A, the teachings of the disclosure can beimplemented in a network interface 343 of a high definition television(HDTV) 337. The HDTV 337 includes a HDTV control module 338, a display339, a power supply 340, memory 341, a storage device 342, the networkinterface 343, and an external interface 345.

The HDTV 337 can receive input signals from the network interface 343and/or the external interface 345, which can send and receiveinformation via cable, broadband Internet, and/or satellite. The HDTVcontrol module 338 may process the input signals, including encoding,decoding, filtering, and/or formatting, and generate output signals. Theoutput signals may be communicated to one or more of the display 339,memory 341, the storage device 342, the network interface 343, and theexternal interface 345.

Memory 341 may include random access memory (RAM) and/or nonvolatilememory such as flash memory, phase change memory, or multi-state memory,in which each memory cell has more than two states. The storage device342 may include an optical storage drive, such as a DVD drive, and/or ahard disk drive (HDD). The HDTV control module 338 communicatesexternally via the network interface 343 and/or the external interface345. The power supply 340 provides power to the components of the HDTV337.

Referring now to FIG. 7B, the teachings of the disclosure may beimplemented in a network interface 352 of a vehicle 346. The vehicle 346may include a vehicle control system 347, a power supply 348, memory349, a storage device 350, and the network interface 352. The vehiclecontrol system 347 may be a powertrain control system, a body controlsystem, an entertainment control system, an anti-lock braking system(ABS), a navigation system, a telematics system, a lane departuresystem, an adaptive cruise control system, etc.

The vehicle control system 347 may communicate with one or more sensors354 and generate one or more output signals 356. The sensors 354 mayinclude temperature sensors, acceleration sensors, pressure sensors,rotational sensors, airflow sensors, etc. The output signals 356 maycontrol engine operating parameters, transmission operating parameters,suspension parameters, etc.

The power supply 348 provides power to the components of the vehicle346. The vehicle control system 347 may store data in memory 349 and/orthe storage device 350. Memory 349 may include random access memory(RAM) and/or nonvolatile memory such as flash memory, phase changememory, or multi-state memory, in which each memory cell has more thantwo states. The storage device 350 may include an optical storage drive,such as a DVD drive, and/or a hard disk drive (HDD). The vehicle controlsystem 347 may communicate externally using the network interface 352.

Referring now to FIG. 7C, the teachings of the disclosure can beimplemented in a network interface 368 of a cellular phone 358. Thecellular phone 358 includes a phone control module 360, a power supply362, memory 364, a storage device 366, and a cellular network interface367. The cellular phone 358 may include the network interface 368, amicrophone 370, an audio output 372 such as a speaker and/or outputjack, a display 374, and a user input device 376 such as a keypad and/orpointing device.

The phone control module 360 may receive input signals from the cellularnetwork interface 367, the network interface 368, the microphone 370,and/or the user input device 376. The phone control module 360 mayprocess signals, including encoding, decoding, filtering, and/orformatting, and generate output signals. The output signals may becommunicated to one or more of memory 364, the storage device 366, thecellular network interface 367, the network interface 368, and the audiooutput 372.

Memory 364 may include random access memory (RAM) and/or nonvolatilememory such as flash memory, phase change memory, or multi-state memory,in which each memory cell has more than two states. The storage device366 may include an optical storage drive, such as a DVD drive, and/or ahard disk drive (HDD). The power supply 362 provides power to thecomponents of the cellular phone 358.

Referring now to FIG. 7D, the teachings of the disclosure can beimplemented in a network interface 385 of a set top box 378. The set topbox 378 includes a set top control module 380, a display 381, a powersupply 382, memory 383, a storage device 384, and the network interface385.

The set top control module 380 may receive input signals from thenetwork interface 385 and an external interface 387, which can send andreceive information via cable, broadband Internet, and/or satellite. Theset top control module 380 may process signals, including encoding,decoding, filtering, and/or formatting, and generate output signals. Theoutput signals may include audio and/or video signals in standard and/orhigh definition formats. The output signals may be communicated to thenetwork interface 385 and/or to the display 381. The display 381 mayinclude a television, a projector, and/or a monitor.

The power supply 382 provides power to the components of the set top box378. Memory 383 may include random access memory (RAM) and/ornonvolatile memory such as flash memory, phase change memory, ormulti-state memory, in which each memory cell has more than two states.The storage device 384 may include an optical storage drive, such as aDVD drive, and/or a hard disk drive (HDD).

Referring now to FIG. 7E, the teachings of the disclosure can beimplemented in a network interface 394 of a mobile device 389. Themobile device 389 may include a mobile device control module 390, apower supply 391, memory 392, a storage device 393, the networkinterface 394, and an external interface 399.

The mobile device control module 390 may receive input signals from thenetwork interface 394 and/or the external interface 399. The externalinterface 399 may include USB, infrared, and/or Ethernet. The inputsignals may include compressed audio and/or video, and may be compliantwith the MP3 format. Additionally, the mobile device control module 390may receive input from a user input 396 such as a keypad, touchpad, orindividual buttons. The mobile device control module 390 may processinput signals, including encoding, decoding, filtering, and/orformatting, and generate output signals.

The mobile device control module 390 may output audio signals to anaudio output 397 and video signals to a display 398. The audio output397 may include a speaker and/or an output jack. The display 398 maypresent a graphical user interface, which may include menus, icons, etc.The power supply 391 provides power to the components of the mobiledevice 389. Memory 392 may include random access memory (RAM) and/ornonvolatile memory such as flash memory, phase change memory, ormulti-state memory, in which each memory cell has more than two states.The storage device 393 may include an optical storage drive, such as aDVD drive, and/or a hard disk drive (HDD). The mobile device may includea personal digital assistant, a media player, a laptop computer, agaming console or other mobile computing device.

Those skilled in the art can now appreciate from the foregoingdescription that the broad teachings of the disclosure can beimplemented in a variety of forms. Therefore, while this disclosureincludes particular examples, the true scope of the disclosure shouldnot be so limited since other modifications will become apparent to theskilled practitioner upon a study of the drawings, the specification andthe following claims.

1. A system, comprising: a first-in first-out (FIFO) module thatreceives records having dynamic frequency selection (DFS) informationgenerated based on pulses received, and that generates a control signalfor every N of said records received, where N is an integer greater than1; a polling module that selectively polls said FIFO module, and thatreads M of said records received by said FIFO module, where M is aninteger greater than or equal to 1 and less than N; a data extractionmodule that extracts said DFS information from said N of said recordswhen said control signal is received, and that selectively extracts saidDFS information from said M of said records; and a control module thatdetermines whether said pulses are a type of radar based on said DFSinformation extracted from at least N of (N+M) of said records.
 2. Thesystem of claim 1 wherein said DFS information comprises pulse widthsand pulse repetition rates of said pulses, signal strength of radiofrequency (RF) signals in said pulses, and whether said pulses are oneof a tone type and a chirp type radar pulses.
 3. The system of claim 1wherein said polling module polls said FIFO module when said DFSinformation extracted from a predetermined number of records out of saidN of said records indicates that said pulses are not radar pulses. 4.The system of claim 1 further comprising a buffer module that storessaid DFS information extracted by said data extraction module.
 5. Thesystem of claim 1 wherein said pulses are received from at least oneburst of radar.
 6. The system of claim 5 wherein said control moduledetermines that said pulses are a type of tone radar when: said DFSinformation extracted from each of said at least N of said (N+M) of saidrecords includes information that a corresponding one of said pulses isa tone radar pulse; an average of pulse widths in said DFS informationextracted from each of said at least N of said (N+M) of said recordsapproximately matches a pulse width of a predetermined type of toneradar; a difference between a maximum and a minimum of said pulse widthsis less than a predetermined threshold; and pulse repetition intervalsin said DFS information extracted from a predetermined number of said atleast N of said (N+M) of said records approximately match a pulserepetition interval of said predetermined type of tone radar.
 7. Thesystem of claim 5 wherein said control module determines that saidpulses are a type of chirp radar when: said DFS information extractedfrom each of said at least N of said (N+M) of said records includesinformation that a corresponding one of said pulses is a chirp radarpulse; pulse widths in said DFS information extracted from said at leastN of said (N+M) of said records approximately match pulse widths of apredetermined type of chirp radar; and pulse repetition intervals insaid DFS information extracted from a predetermined number of said atleast N of said (N+M) of said records approximately match pulserepetition intervals of said predetermined type of chirp radar.
 8. Thesystem of claim 1 wherein said control module determines whether saidpulses are a type of one of a tone radar and a chirp radar based onpulse widths in said DFS information extracted from at least N of saidrecords when said pulses are received from at least one burst of radarand when said pulses are separated by at least one data packet.
 9. Thesystem of claim 8 wherein said control module determines that saidpulses are a type of tone radar when said pulse widths match a pulsewidth of a predetermined type of tone radar and wherein said controlmodule determines that said pulses are a type of chirp radar when saidpulse widths match pulse widths of a predetermined type of chirp radar.10. The system of claim 1 wherein said pulses comprise radio frequency(RF) signals and said DFS information includes a number ofzero-crossings of said RF signals per bin for a plurality of bins, wheresaid bin is a time period greater than or equal to a smallest of pulsewidths of predetermined types of radar pulses.
 11. The system of claim10 wherein said control module determines that said pulses are tone typeradar pulses when a difference between maximum and minimum values ofsaid number of zero-crossings is less than a predetermined threshold.12. The system of claim 10 wherein said control module determines thatsaid pulses are chirp type radar pulses when: differences between saidnumber of zero-crossings in adjacent bins are greater than a firstpredetermined threshold; and a rate of change of said number ofzero-crossings in successive bins is less than a second predeterminedthreshold.
 13. A medium access controller (MAC) comprising the system ofclaim 1 and further comprising a physical layer module (PHY) thatcommunicates said records to the MAC.
 14. A wireless network devicecomprising the MAC of claim 13 and further comprising at least oneantenna that receives said pulses and that communicates said pulses tosaid PHY.
 15. A radar detection device comprising the system of claim 1.16. A method, comprising: receiving records having dynamic frequencyselection (DFS) information generated based on pulses received in afirst-in first-out (FIFO) module; generating a control signal for everyN of said records received, where N is an integer greater than 1;selectively polling said FIFO module; reading M of said records receivedby said FIFO module, where M is an integer greater than or equal to 1and less than N; extracting said DFS information from said N of saidrecords when said control signal is received; selectively extractingsaid DFS information from said M of said records; and determiningwhether said pulses are a type of radar based on said DFS informationextracted from at least N of said (N+M) of said records.
 17. The methodof claim 16 further comprising receiving said records having said DFSinformation that includes pulse widths and pulse repetition rates ofsaid pulses, signal strength of radio frequency (RF) signals in saidpulses, and whether said pulses are one of a tone type and a chirp typeradar pulses.
 18. The method of claim 16 further comprising polling saidFIFO module when said DFS information extracted from a predeterminednumber of records out of said N of said records indicates that saidpulses are not radar pulses.
 19. The method of claim 16 furthercomprising storing said DFS information extracted by said dataextraction module.
 20. The method of claim 16 further comprisingreceiving said pulses from at least one burst of radar.
 21. The methodof claim 20 further comprising determining that said pulses are a typeof tone radar when: said DFS information extracted from each of said atleast N of said (N+M) of said records includes information that acorresponding one of said pulses is a tone radar pulse; an average ofpulse widths in said DFS information extracted from each of said atleast N of said (N+M) of said records approximately matches a pulsewidth of a predetermined type of tone radar; a difference between amaximum and a minimum of said pulse widths is less than a predeterminedthreshold; and pulse repetition intervals in said DFS informationextracted from a predetermined number of said at least N of said (N+M)of said records approximately match a pulse repetition interval of saidpredetermined type of tone radar.
 22. The method of claim 20 furthercomprising determining that said pulses are a type of chirp radar when:said DFS information extracted from each of said at least N of said(N+M) of said records includes information that a corresponding one ofsaid pulses is a chirp radar pulse; pulse widths in said DFS informationextracted from said at least N of said (N+M) of said recordsapproximately match pulse widths of a predetermined type of chirp radar;and pulse repetition intervals in said DFS information extracted from apredetermined number of said at least N of said (N+M) of said recordsapproximately match pulse repetition intervals of said predeterminedtype of chirp radar.
 23. The method of claim 16 further comprisingdetermining whether said pulses are a type of one of a tone radar and achirp radar based on pulse widths in said DFS information extracted fromat least N of said records when said pulses are received from at leastone burst of radar and when said pulses are separated by at least onedata packet.
 24. The method of claim 23 further comprising determiningthat said pulses are a type of tone radar when said pulse widths match apulse width of a predetermined type of tone radar and determining thatsaid pulses are a type of chirp radar when said pulse widths match pulsewidths of a predetermined type of chirp radar.
 25. The method of claim16 further comprises receiving said records when said pulses includeradio frequency (RF) signals and wherein said DFS information includes anumber of zero-crossings of said RF signals per bin for a plurality ofbins, where said bin is a time period greater than or equal to asmallest of pulse widths of predetermined types of radar pulses.
 26. Themethod of claim 25 further comprising determining that said pulses aretone type radar pulses when a difference between maximum and minimumvalues of said number of zero-crossings is less than a predeterminedthreshold.
 27. The method of claim 25 further comprises determining thatsaid pulses are chirp type radar pulses when: differences between saidnumber of zero-crossings in adjacent bins are greater than a firstpredetermined threshold; and a rate of change of said number ofzero-crossings in successive bins is less than a second predeterminedthreshold.
 28. The method of claim 16 further comprising communicatingbetween a physical layer module (PHY) and a medium access controller(MAC) and communicating said records to said MAC.
 29. The method ofclaim 28 further comprising receiving said pulses via at least oneantenna in a wireless network device and communicating said pulses tosaid PHY.
 30. The method of claim 16 further comprising determiningwhether said pulses include radar when said pulses are received by aradar detection device.
 31. A system, comprising: first-in first-out(FIFO) means for receiving records having dynamic frequency selection(DFS) information generated based on pulses received, and generating acontrol signal for every N of said records received, where N is aninteger greater than 1; polling means for selectively polling said FIFOmeans and reading M of said records received by said FIFO means, where Mis an integer greater than or equal to 1 and less than N; dataextraction means for extracting said DFS information from said N of saidrecords when said control signal is received, and selectively extractingsaid DFS information from said M of said records; and control means fordetermining whether said pulses are a type of radar based on said DFSinformation extracted from at least N of (N+M) of said records.
 32. Thesystem of claim 31 wherein said DFS information comprises pulse widthsand pulse repetition rates of said pulses, signal strength of radiofrequency (RF) signals in said pulses, and whether said pulses are oneof a tone type and a chirp type radar pulses.
 33. The system of claim 31wherein said polling means polls said FIFO means when said DFSinformation extracted from a predetermined number of records out of saidN of said records indicates that said pulses are not radar pulses. 34.The system of claim 31 further comprising buffer means for storing saidDFS information extracted by said data extraction means.
 35. The systemof claim 31 wherein said pulses are received from at least one burst ofradar.
 36. The system of claim 35 wherein said control means determinesthat said pulses are a type of tone radar when: said DFS informationextracted from each of said at least N of said (N+M) of said recordsincludes information that a corresponding one of said pulses is a toneradar pulse; an average of pulse widths in said DFS informationextracted from each of said at least N of said (N+M) of said recordsapproximately matches a pulse width of a predetermined type of toneradar; a difference between a maximum and a minimum of said pulse widthsis less than a predetermined threshold; and pulse repetition intervalsin said DFS information extracted from a predetermined number of said atleast N of said (N+M) of said records approximately match a pulserepetition interval of said predetermined type of tone radar.
 37. Thesystem of claim 35 wherein said control means determines that saidpulses are a type of chirp radar when: said DFS information extractedfrom each of said at least N of said (N+M) of said records includesinformation that a corresponding one of said pulses is a chirp radarpulse; pulse widths in said DFS information extracted from said at leastN of said (N+M) of said records approximately match pulse widths of apredetermined type of chirp radar; and pulse repetition intervals insaid DFS information extracted from a predetermined number of said atleast N of said (N+M) of said records approximately match pulserepetition intervals of said predetermined type of chirp radar.
 38. Thesystem of claim 31 wherein said control means determines whether saidpulses are a type of one of a tone radar and a chirp radar based onpulse widths in said DFS information extracted from at least N of saidrecords when said pulses are received from at least one burst of radarand when said pulses are separated by at least one data packet.
 39. Thesystem of claim 38 wherein said control means determines that saidpulses are a type of tone radar when said pulse widths match a pulsewidth of a predetermined type of tone radar and wherein said controlmeans determines that said pulses are a type of chirp radar when saidpulse widths match pulse widths of a predetermined type of chirp radar.40. The system of claim 31 wherein said pulses comprise radio frequency(RF) signals and said DFS information includes a number ofzero-crossings of said RF signals per bin for a plurality of bins, wheresaid bin is a time period greater than or equal to a smallest of pulsewidths of predetermined types of radar pulses.
 41. The system of claim40 wherein said control means determines that said pulses are tone typeradar pulses when a difference between maximum and minimum values ofsaid number of zero-crossings is less than a predetermined threshold.42. The system of claim 40 wherein said control means determines thatsaid pulses are chirp type radar pulses when: differences between saidnumber of zero-crossings in adjacent bins are greater than a firstpredetermined threshold; and a rate of change of said number ofzero-crossings in successive bins is less than a second predeterminedthreshold.
 43. A medium access controller (MAC) comprising the system ofclaim 31 and further comprising physical layer means (PHY) forcommunicating said records to the MAC.
 44. A wireless network devicecomprising the MAC of claim 43 and further comprising at least oneantenna means for receiving said pulses and communicating said pulses tosaid PHY means.
 45. A radar detection device comprising the system ofclaim 31.